The Fed needs to drive down borrowing rates low because the economy isn't growing fast enough to reduce high unemployment, Bernanke said in a speech to the Indiana Economics Club. The unemployment rate is 8.1 percent.

Low rates could help lower the federal budget deficit by reducing the government's borrowing costs and generating more tax revenue through stronger growth, Bernanke said.

Bernanke also cautioned Congress against changing the law so it could review the Fed's interest-rate policy discussions. Such a step would improperly inject political pressure into those talks and make Fed policymakers less likely to act, Bernanke warns.

The speech comes just weeks after the Fed voted at its Sept. 12-13 meeting to purchase $40 billion a month in mortgage-backed securities to push mortgage rates lower and help boost the housing market. The Fed left the program open ended, saying only that it would keep buying the bonds until the job market showed substantial improvement.

The Fed also said at the September meeting it plans to keep its benchmark short-term interest rate near zero through at least mid-2015, six months longer than its previous target date of late 2014.

The Fed's action was approved on an 11-1 vote.

The U.S. economy is struggling more than three years after the Great Recession ended. High unemployment and weak pay growth has made consumers more cautious about spending, which has hurt manufacturing and slowed broader growth.

The Fed is hoping to make home buying more attractive to help the broader economy. When home prices rise, people typically feel wealthier and spend more. Consumer spending drives nearly 70 percent of economic activity.